The Toyota Prius is a full hybrid electric

Hybrid electric vehicle

A hybrid electric vehicle is a type of hybrid vehicle and electric vehicle which combines a conventional internal combustion engine propulsion system with an electric propulsion system. The presence of the electric powertrain is intended to achieve either better fuel economy than a conventional...

 mid-size

Mid-size car

A mid-size car is the North American/Australian standard for an automobile with a size equal to or greater than that of a compact...

 hatchback

Hatchback

A Hatchback is a car body style incorporating a shared passenger and cargo volume, with rearmost accessibility via a rear third or fifth door, typically a top-hinged liftgate—and features such as fold-down rear seats to enable flexibility within the shared passenger/cargo volume. As a two-box...

, formerly a compact

Compact car

A compact car , or small family car , is a classification of cars which are larger than a supermini but smaller than or equal to a mid-size car...

 sedan developed and manufactured by the Toyota Motor Corporation

Toyota Motor Corporation

, , , commonly known simply as Toyota and abbreviated as TMC, is a multinational automaker headquartered in Toyota, Aichi, Japan. In 2010, Toyota Motor Corporation employed 317,734 people worldwide, and was the world's largest automobile manufacturer by production.The company was founded by...

. The EPA and California Air Resources Board

California Air Resources Board

The California Air Resources Board, also known as CARB or ARB, is the "clean air agency" in the government of California. Established in 1967 in the Mulford-Carrell Act, combining the Bureau of Air Sanitation and the Motor Vehicle Pollution Control Board, CARB is a department within the...

 (CARB) rate the Prius as among the cleanest vehicles sold in the United States based on smog

Smog

Smog is a type of air pollution; the word "smog" is a portmanteau of smoke and fog. Modern smog is a type of air pollution derived from vehicular emission from internal combustion engines and industrial fumes that react in the atmosphere with sunlight to form secondary pollutants that also combine...

-forming emissions.

The Prius first went on sale in Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

 in 1997, making it the first mass-produced hybrid vehicle. It was subsequently introduced worldwide in 2001.